Pipe coupling



FIG. 1 is a perspective view of a first embodiment of our design for a pipe coupling;

FIG. 2 is a side view of the pipe coupling shown in FIG. 1, the opposite side, the top and bottom views being identical thereto;

FIG. 3 is an end view of the pipe coupling shown in FIG. 1, the opposite end view being identical;

FIG. 4 is a perspective view of a second embodiment of our design for a pipe coupling;

FIG. 5 is a side view of the pipe coupling shown in FIG. 4, the opposite side, the top and bottom views being identical thereto; and,

FIG. 6 is an end view of the pipe coupling shown in FIG. 4, the opposite end view being identical.

The broken lines shown in the various Figures are shown for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a pipe coupling, as shown and described. 